A method for the rapid preparation of a fully siliceous ssz-13 zeolite using a directing agent method

Abstract

The application provides a method for rapidly preparing full-silicon SSZ-13 zeolite by using a directing agent, and belongs to the technical field of zeolite synthesis. The full-silicon SSZ-13 zeolite is rapidly synthesized in a solvent-free system by using the directing agent, and the technical effect is achieved. The full-silicon SSZ-13 zeolite prepared by the application does not need to use any zeolite seed, that is, the use of toxic fluorine species in the preparation process of the seed is avoided, so that the whole preparation process does not involve any fluorine species. The preparation method has very short crystallization time, and has great significance for improving the production efficiency of the full-silicon SSZ-13 zeolite.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of zeolite synthesis, and particularly relates to a method for rapidly preparing full-silicon SSZ-13 zeolite by a directing agent method. BACKGROUND

[0002] The SSZ-13 zeolite has a three-dimensional eight-membered ring pore structure, is composed of CHA cages and double six-membered ring secondary structure units, and has a pore size of 4.1-4.2 angstroms. It has excellent performance in adsorption separation, MTO and NH3-SCR processes.

[0003] In the 1980s, Zones et al. applied for US patent US4544538, which first disclosed a method for synthesizing a silicon-aluminum SSZ-13 zeolite. The organic template used is N,N,N-trimethyl-1-adamantammonium cation. Subsequently, researchers have successively found that choline chloride, tetraethylammonium hydroxide, benzyltrimethylammonium and other organic template agents can be used to successfully direct the preparation of a silicon-aluminum SSZ-13 zeolite. Although these syntheses are carried out under alkaline conditions, the prepared product has a relatively low silicon-aluminum ratio (Si / Al is less than 40). Professor Camblor's research group first added fluoride ions in the synthesis system to successfully prepare a full-silicon SSZ-13 zeolite. However, the fluoride species used in the synthesis is highly toxic and cannot be used for industrial production (Chem. Commun., 1998, 17, 1881). Recently, Professor Fan Wei's research group first prepared a full-silicon SSZ-13 zeolite in a non-fluorine alkaline system by a dry gel conversion method (Angew. Chem. Int. Ed., 2018, 57, 3607). However, a large amount of N,N,N-trimethyl-1-adamantammonium cation template (template / SiO2 is greater than 0.5) needs to be added in the synthesis, and the crystallization time is super long, which needs 15 days. The addition of a large amount of template and the super long crystallization time in the synthesis make the preparation cost of the full-silicon SSZ-13 zeolite high, which limits its application to some extent.

[0004] Recently, Wu et al. applied for Chinese patent CN201810413258.2, which reported a method for synthesizing a silicon-rich SSZ-13 zeolite by seed-assisted synthesis in a non-fluorine system under a low template content condition. It should be noted that the full-silicon seed added needs to be synthesized by using a fluorine-containing system, and in addition, although the solvent water is used as little as possible, solvent water is still added, which belongs to hydrothermal synthesis. In addition, the synthesis time is still relatively long and does not reach the minute level. SUMMARY

[0005] The present application aims at overcoming the deficiencies in the prior art, and provides a method for rapidly preparing a full-silicon SSZ-13 zeolite by a directing agent method.

[0006] To achieve the above-mentioned purposes of the application, the application provides the following technical solutions.

[0007] The application provides a method for rapidly preparing a full-silicon SSZ-13 zeolite by using a directing agent, comprising the following steps:

[0008] The alkali source, the aqueous organic template solution, the silicon source and the directing agent are sequentially mixed and ground, and then subjected to crystallization treatment to obtain the full-silicon SSZ-13 zeolite.

[0009] The alkali source comprises sodium hydroxide and / or sodium oxide, the aqueous organic template solution comprises an aqueous N,N,N-trimethyl-1-adamantammonium hydroxide solution, and the silicon source comprises solid silica gel and / or white carbon black.

[0010] Further, the mass concentration of the aqueous organic template solution is 40-60 wt%.

[0011] Further, the mass ratio of the alkali source, the aqueous organic template solution, the silicon source and the directing agent is 0.05-0.2:0.1-2.0:1.5-2.0:0.2-1.0.

[0012] Further, the preparation method of the directing agent comprises the following steps:

[0013] a. mixing sodium hydroxide and solid silica gel in an aqueous N,N,N-trimethyl-1-adamantammonium hydroxide solution to obtain a mixed solution;

[0014] b. heating the mixed solution to obtain the directing agent.

[0015] Further, in step a, the mass ratio of the sodium hydroxide, the solid silica gel and the aqueous N,N,N-trimethyl-1-adamantammonium hydroxide solution is 0.2-0.3:1.5-2.5:1.5-2.0.

[0016] Further, in step a, the mass concentration of the aqueous N,N,N-trimethyl-1-adamantammonium hydroxide solution is 40-50%.

[0017] Further, in step b, the heating temperature is 110-160 DEG C, and the heating time is 1-3 h.

[0018] Further, the mixing and grinding time is 5-15 min.

[0019] Further, the crystallization treatment temperature is 160-200 DEG C, and the crystallization treatment time is 30-100 min.

[0020] The application has the following beneficial effects:

[0021] 1. The full-silicon SSZ-13 zeolite prepared by the method has good crystallinity and purity, and the production process does not use high-toxicity fluorine species, so that unnecessary loss in the production process is reduced.

[0022] 2. The full-silicon SSZ-13 zeolite prepared by the method does not need to use any zeolite seed, that is, the use of toxic fluorine species in the preparation of the seed is avoided, so that the entire preparation process does not involve any fluorine species.

[0023] 3. The full-silicon SSZ-13 zeolite prepared by the method has a very short crystallization time, which is of great significance to improve the production efficiency.

[0024] 4. The inorganic raw materials used in the method are environmentally friendly and low in price, and the use amount of the template is small, so that the synthesis cost is greatly reduced, so that the method has important significance in the field of actual chemical production. BRIEF DESCRIPTION OF DRAWINGS

[0025] Figure 1 XRD spectrum of the full-silicon SSZ-13 zeolite molecular sieve obtained in Example 1 of the present application;

[0026] Figure 2 1000 times scanning electron microscope photograph of the full-silicon SSZ-13 zeolite molecular sieve obtained in Example 1 of the present application;

[0027] Figure 3 30000 times scanning electron microscope photograph of the full-silicon SSZ-13 zeolite molecular sieve obtained in Example 1 of the present application. DETAILED DESCRIPTION

[0028] The present application provides a method for rapidly preparing full-silicon SSZ-13 zeolite by a directing agent method, comprising the following steps:

[0029] The base source, the organic template aqueous solution, the silicon source and the directing agent are sequentially mixed, ground and crystallized to obtain the full-silicon SSZ-13 zeolite.

[0030] The base source comprises sodium hydroxide and / or sodium oxide, the organic template aqueous solution comprises N,N,N-trimethyl-1-adamantane ammonium hydroxide aqueous solution, and the silicon source comprises solid silica gel and / or white carbon black.

[0031] In the present application, the base source is preferably sodium hydroxide.

[0032] In the present application, the organic template aqueous solution is preferably N,N,N-trimethyl-1-adamantane ammonium hydroxide aqueous solution (TMdaOH).

[0033] In the present application, the mass concentration of the organic template aqueous solution is 40-60wt%, preferably 45-55wt%, and further preferably 50wt%.

[0034] In the present application, the silicon source is preferably solid silica gel.

[0035] In the present application, the mass ratio of the alkali source, the organic template aqueous solution, the silicon source and the directing agent is 0.05-0.2:0.1-2.0:1.5-2.0:0.2-1.0, preferably 0.1-0.17:0.16-1.92:1.6-1.9:0.3-0.9, and further preferably 0.15:0.8-1.0:0.84:0.45.

[0036] In the present application, the preparation method of the directing agent comprises the following steps:

[0037] a. mixing sodium hydroxide and solid silica gel in N,N,N-trimethyl-1-adamantammonium hydroxide aqueous solution to obtain a mixed solution;

[0038] b. heating the mixed solution to obtain the directing agent.

[0039] In the present application, in step a, the mass ratio of the sodium hydroxide, the solid silica gel and the N,N,N-trimethyl-1-adamantammonium hydroxide aqueous solution is 0.2-0.3:1.5-2.5:1.5-2.0, preferably 0.21-0.25:1.8-2.4:1.6-1.9, and further preferably 0.22:2.24:1.84.

[0040] In the present application, in step a, the mass concentration of the N,N,N-trimethyl-1-adamantammonium hydroxide aqueous solution is 40-50%, preferably 42-48%, and further preferably 45%.

[0041] In the present application, in step b, the heating temperature is 110-160℃, and the heating time is 1-3h; preferably, the heating temperature is 120-150℃, and the heating time is 1-2h; and further preferably, the heating temperature is 140℃, and the heating time is 2h.

[0042] In the present application, the mixing and grinding time is 5-15min, preferably 8-12min, and further preferably 10min.

[0043] In the present application, the temperature of the crystallization treatment is 160-200°C, and the time of the crystallization treatment is 30-100 min; preferably, the temperature of the crystallization treatment is 170-190°C, and the time of the crystallization treatment is 40-90 min; further preferably, the temperature of the crystallization treatment is 180°C, and the time of the crystallization treatment is 60 min.

[0044] The technical solutions provided by the present application are described in detail below in combination with examples, but they should not be understood as limiting the scope of protection of the present application.

[0045] Example 1

[0046] Preparation of the directing agent:

[0047] 0.22 g of sodium hydroxide was added to 2.24 g of a 41% mass fraction TMdaOH aqueous solution, stirred uniformly, then 1.84 g of solid silica gel was added, and stirring was continued until the mixture was uniform. Reaction was carried out at 140°C for 2 hours until it was clear, and the directing agent was obtained.

[0048] Preparation of the all-silica SSZ-13 zeolite:

[0049] 0.17 g of NaOH, 1.6 g of a 50% mass fraction TMdaOH aqueous solution, 1.84 g of solid silica gel, and 0.9 g of the directing agent were ground in a mortar for 10 min, then the solid mixture was added to a polytetrafluoroethylene stainless steel reaction kettle, and the crystallization treatment was carried out at 160°C for 100 min until complete crystallization, the product was suction filtered, and the product was obtained after drying.

[0050] The product obtained was analyzed by X-ray diffraction, and the result is shown in Figure 1 From the scanning electron microscope photos, it can be seen that the product synthesized has a relatively uniform morphology Figure 2 , and the morphology of the product is small-grained cube Figure 3 , and the particle size is about 500 nm.

[0051] Example 2

[0052] Preparation of the directing agent:

[0053] 0.24 g of sodium hydroxide was added to 2.06 g of a 45% mass fraction TMdaOH aqueous solution, stirred uniformly, then 1.75 g of solid silica gel was added, and stirring was continued until the mixture was uniform. Reaction was carried out at 150°C for 1.5 hours until it was clear, and the directing agent was obtained.

[0054] A 0.17 g of NaOH, 1.6 g of a 50% by mass TMdaOH aqueous solution, 1.84 g of solid silica gel, and 0.9 g of the directing agent were ground in a mortar for 10 min, and then the solid mixture was added to a polytetrafluoroethylene stainless steel autoclave, and the crystallization treatment was performed at 160°C for 90 min to complete the crystallization, and the product was suction filtered and dried to obtain the product.

[0055] The product was analyzed by X-ray diffraction to be a full-silica SSZ-13 zeolite, and the product had a similar morphology and size to Example 1.

[0056] Example 3

[0057] Preparation of the directing agent:

[0058] A 0.25 g of sodium hydroxide was added to 1.84 g of a 45% by mass TMdaOH aqueous solution, and stirred until uniform, and then 1.84 g of solid silica gel was added, and stirred until uniform. The reaction was performed at 140°C for 2 hours until clear to obtain the directing agent.

[0059] Preparation of the full-silica SSZ-13 zeolite:

[0060] A 0.05 g of NaOH, 0.16 g of a 50% by mass TMdaOH aqueous solution, 1.84 g of solid silica gel, and 0.9 g of the directing agent were ground in a mortar for 10 min, and then the solid mixture was added to a polytetrafluoroethylene stainless steel autoclave, and the crystallization treatment was performed at 200°C for 30 min to complete the crystallization, and the product was suction filtered and dried to obtain the product.

[0061] The product was analyzed by X-ray diffraction to be a full-silica SSZ-13 zeolite, and the product had a similar morphology and size to Example 1.

[0062] Example 4

[0063] Preparation of the directing agent:

[0064] A 0.3 g of sodium hydroxide was added to 2.55 g of a 50% by mass TMdaOH aqueous solution, and stirred until uniform, and then 1.84 g of solid silica gel was added, and stirred until uniform. The reaction was performed at 150°C for 2 hours until clear to obtain the directing agent.

[0065] Preparation of the full-silica SSZ-13 zeolite:

[0066] A 0.1 g of NaOH, 0.8 g of a 50% by mass TMdaOH aqueous solution, 1.84 g of solid silica gel, and 0.3 g of the directing agent were ground in a mortar for 10 min, and then the solid mixture was added to a polytetrafluoroethylene stainless steel autoclave, and the crystallization treatment was performed at 180°C for 60 min to complete the crystallization, and the product was suction filtered and dried to obtain the product.

[0067] The product was analyzed by X-ray diffraction and was found to be a fully siliceous SSZ-13 zeolite. The product had a similar morphology and size as Example 1.

[0068] Example 5

[0069] Preparation of the directing agent:

[0070] 0.22 g of sodium hydroxide was added to 2.24 g of a 41% mass fraction TMdaOH aqueous solution, stirred until uniform, and then 1.84 g of solid silica gel was added and stirring was continued until uniform. The reaction was carried out at 140°C for 2 hours until clear, and the directing agent was obtained.

[0071] Preparation of a fully siliceous SSZ-13 zeolite:

[0072] 0.15 g of NaOH, 1.92 g of a 50% mass fraction TMdaOH aqueous solution, 1.84 g of white carbon black, and 0.45 g of the directing agent were ground in a mortar for 10 min, and then the solid mixture was added to a polytetrafluoroethylene stainless steel autoclave, and the crystallization was carried out at 160°C for 90 min until complete crystallization, and the product was suction filtered and dried to obtain the product.

[0073] The product was analyzed by X-ray diffraction and was found to be a fully siliceous SSZ-13 zeolite. The product had a similar morphology and size as Example 1.

[0074] As can be seen from the above examples, the present application provides a method for rapidly preparing a fully siliceous SSZ-13 zeolite by a directing agent method. The fully siliceous SSZ-13 zeolite prepared by the present application not only maintains good crystallinity and purity, but also does not use highly toxic fluorine species in the entire production process, thereby reducing unnecessary losses in the production process. As can be seen from the scanning electron microscope photos, the synthesized product has a relatively uniform morphology, and the product morphology is a small-grained cube with a particle size of about 500 nm.

[0075] The above only describes the preferred embodiments of the present application, and it should be noted that for those skilled in the art, without departing from the principles of the present application, a number of improvements and refinements can be made, and these improvements and refinements should also be considered as the protection scope of the present application.

Claims

1. A method for rapid preparation of all-silica SSZ-13 zeolite using a directing agent, characterized in that, Includes the following steps: The all-silica SSZ-13 zeolite is obtained by sequentially mixing, grinding, and crystallizing an alkaline source, an aqueous organic template agent, a silicon source, and a directing agent. The alkaline source comprises sodium hydroxide and / or sodium oxide, the organic template agent aqueous solution comprises an aqueous solution of N,N,N-trimethyl-1-adamantane ammonium hydroxide, and the silicon source comprises solid silica gel and / or silica. The mass ratio of the alkali source, the organic template agent aqueous solution, the silicon source, and the directing agent is 0.05–0.2:0.1–2.0:1.5–2.0:0.2–1.0; The preparation method of the directing agent includes the following steps: a. Sodium hydroxide and solid silica gel are mixed in an aqueous solution of N,N,N-trimethyl-1-adamantane ammonium hydroxide to obtain a mixed solution; b. Heat the mixed solution until it becomes clear to obtain the directing agent; In step a, the mass ratio of sodium hydroxide, solid silica gel, and N,N,N-trimethyl-1-adamantane ammonium hydroxide aqueous solution is 0.2-0.3:1.5-2.5:1.5-2.0; The crystallization treatment temperature is 160–200°C, and the crystallization treatment time is 30–100 min.

2. The method for rapid preparation of all-silica SSZ-13 zeolite using the directing agent method according to claim 1, characterized in that, The mass concentration of the organic template agent aqueous solution is 40-60 wt%.

3. The method for rapid preparation of all-silica SSZ-13 zeolite using the directing agent method according to claim 1, characterized in that, In step a, the mass concentration of the N,N,N-trimethyl-1-adamantane ammonium hydroxide aqueous solution is 40-50%.

4. The method for rapid preparation of all-silica SSZ-13 zeolite using the directing agent method according to claim 3, characterized in that, In step b, the heating reaction temperature is 110–160°C, and the heating reaction time is 1–3 hours.

5. The method for rapid preparation of all-silica SSZ-13 zeolite using the directing agent method according to claim 4, characterized in that, The mixing and grinding time is 5 to 15 minutes.

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